The SELECT operator can be used, among other things, to display a value.
The SELECT keyword uses the following syntax:

SELECT What

Based on this, to use it, where it is needed, type SELECT
followed by a number, a word, a string, or an expression. To display a sentence using SELECT,
type it in single-quotes on the right side of this operator. Here is an executed
example:

As mentioned already, unlike PRINT, SELECT can be used to
display more than one value. The values must be separated by commas. Here is an
example:

SELECT 'Hourly Salary', 24.85

This would produce:

Nesting a SELECT Statement

When you create a SELECT statement, what is on the
right side of SELECT must be a value. Here is an example:

SELECT 226.75;

Based on this definition, instead of just being a value, the
thing on the right side of SELECT must be able to produce a value. As we
will see in the next sections, you can create algebraic operation on the right
side of SELECT. Because we mentioned that the thing on the right side must
produce a result, you can as well use another SELECT statement that it itself
evaluates to a result. To distinguish the SELECT sections, the second one should
be included in parentheses. Here is an example:

SELECT (SELECT 448.25);
GO

When one SELECT statement is created after another,
the second is referred to as nested.

Just as you can nest one SELECT statement inside of another,
you can also nest one statement in another statement that itself is nested. Here
is an example:

SELECT (SELECT (SELECT 1350.75));
GO

SELECT This AS That

In the above introductions, we used either PRINT
or SELECT to display something in the query window. One of the
characteristics of SELECT is that it can segment its result in
different sections. SELECT represents each value in a section called a
column. Each column is represented with a name also called a caption. By
default, the caption displays as "(No column name)". If you want
to use your own caption, on the right side of an expression, type the AS
keyword followed by the desired caption. The item on the right side of the AS keyword must be
considered as one word. Here is an
example:

SELECT 24.85 AS HourlySalary;

This would produce:

You can also include the item on the right side of AS
in single-quotes. Here is an
example:

SELECT 24.85 AS 'HourlySalary';

If the item on the right side of AS is
in different words, you should include it in single-quotes or put them in inside of an opening square bracket
"[" and a closing square bracket "]". Here is an
example:

SELECT 24.85 AS 'Hourly Salary';

If you create different sections, separated by a
comma, you can follow each with AS and a caption. Here is an
example: